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Commit a8c1f2af authored by Haiyang Zhang's avatar Haiyang Zhang Committed by Greg Kroah-Hartman
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hv_netvsc: Fix unwanted wakeup in netvsc_attach() 



commit f6f13c125e05603f68f5bf31f045b95e6d493598 upstream.

When netvsc_attach() is called by operations like changing MTU, etc.,
an extra wakeup may happen while netvsc_attach() calling
rndis_filter_device_add() which sends rndis messages when queue is
stopped in netvsc_detach(). The completion message will wake up queue 0.

We can reproduce the issue by changing MTU etc., then the wake_queue
counter from "ethtool -S" will increase beyond stop_queue counter:
     stop_queue: 0
     wake_queue: 1
The issue causes queue wake up, and counter increment, no other ill
effects in current code. So we didn't see any network problem for now.

To fix this, initialize tx_disable to true, and set it to false when
the NIC is ready to be attached or registered.

Fixes: 7b2ee50c ("hv_netvsc: common detach logic")
Signed-off-by: default avatarHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent aba7251b

drivers/net/hyperv/netvsc.c

+1 −1
Original line number Diff line number Diff line
@@ -110,7 +110,7 @@ static struct netvsc_device *alloc_net_device(void) 


	init_waitqueue_head(&net_device->wait_drain);

	net_device->destroy = false;

	net_device->tx_disable = false;

	net_device->tx_disable = true;



	net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT;

	net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT;

drivers/net/hyperv/netvsc_drv.c

+3 −0
Original line number Diff line number Diff line
@@ -984,6 +984,7 @@ static int netvsc_attach(struct net_device *ndev, 
	}



	/* In any case device is now ready */

	nvdev->tx_disable = false;

	netif_device_attach(ndev);



	/* Note: enable and attach happen when sub-channels setup */
@@ -2336,6 +2337,8 @@ static int netvsc_probe(struct hv_device *dev, 
	else

		net->max_mtu = ETH_DATA_LEN;



	nvdev->tx_disable = false;



	ret = register_netdevice(net);

	if (ret != 0) {

		pr_err("Unable to register netdev.\n");